As you may already know, drug release from a polymeric hydrogel is determined by a number of factors. In general, release efficacy will be determined by diffusion, hydrogel swelling, pore size, reversible drug-polymer interactions, or degradation of labile covalent bonds. Your issue could be in any of these categories, and without further details it would be difficult to tell you which one to troubleshoot. Below are a few useful resources on drug release kinetics from hydrogel matrices which may be of help to you:

Article Hoare TR, Kohane DS. Hydrogels in drug delivery: progress an...

Article Hydrogels for Therapeutic Delivery: Current Developments and...

Article Drug release from hydrogel matrices

Introduce some stimuli-response bonds into the matrix may be an option.

Hi!

First of all, you have to be sure the drug exists in the gel. It is no joke, we had same problem. Next, you should to check probability of accidental chemical crosslinking between functional groups of the gel and the drug. Check question of the drug degradation. Then you can vary concentration of crosslinking agent to obtain gels with different dencity of cross links. May be, you can add any salt solution.

Good luck.

Tatiana

Dear Tatiana,

Please give me the details of salt solution. What to use and how much?This will be handy for me.